Boiler



J. A. FREIDAY Aug. 29, 1933.'

BOILER Filed July. 26, -195o 7 Sheets-.Sheet l Aug. 29, 1933.

J. A. FREIDAY BOILER 7 Sheets-Sheetl 2 Filed July 26, 19:50

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BOILER Filed July 26, .1930 7 Sheets-Sheet 4 MM. I!

J. A. FREIDAY BOILER Filed July 2e, i930 Aug. 29, 1933.

Aug. 29, 1933. 1 A. FREIDAY 1,924,850

BOILER Filed July 26, 1930 7 Sheets-Sheet 6 lf/rvy Snvwntoz www@ Aug'. 29, 1933. l J A FRElDAY 1,924,850

/MM ATTORNEYS Patented Aug. 29, 1933 BOILER Jay A. Freiday, East Orange, N. .I., assignor to Metropolitan Engineering Company, Brooklyn,

N. Y., a corporation of New York Application July 26, 1930. serial No. 470,863

y 9 Claims.

The invention aims to provide a simple and convenient arrangement of the tubes in a boiler whereby the circulation of water and the passage of the gases are improved and certain other advantages are obtained as specified hereinafter. Fig. l is a longitudinal vertical section of a boiler embodying the invention;

Fig. 2 is a vertical cross section thereof approximately on the line 2-2, Fig. 1;

Figs. 3, 4, 5 and 6 `are sections similar'to Fig. 1 showing modifications;

Fig. 7 is a section similar to Fig. 3 showing a modification. Referring first to Figs. 1 and 2, a bank 11 of inclined tubes is arranged above a furnace 12 connected at their ends with headers 13 and 14. The circulation is through risers 15 to a dr'um 16 and thence downward through pipes 17 at the front of the furnace with lower portions 18 ex- 20 tending to the back and into the ends of a bottom header 19. AA water wall of tubes 20 (Fig. 2) extends up at the back of the combustion chamber leading from the bottom header 19 into the headers 13, thus completing the circulating through the inclined tubes 11.

In addition there is a bottom screen of inclined tubes 21 extending over the ash pit 22 and leading from the rear bottom header 19 to a front bottom header 23.

i A water wall of upright tubes 24 extends from the header 23 up to the headers 14. Thus there isA a supplementary circulation through the downcomers 17, 18, header 19, screen 21, header 23, water wall 24 and headers 14 to the steam drum.

The bottom screen of tubes 21 may be omitted, in which case separate downcomers should be provided from the steam drum to the header 23.

Also the water walls of upright tubes may be omitted in which case the downcomers l7`would carry water to the usual mud drum communieating with the lower ends of the headers 13.-

Above the bank of tubes 11 there Ais a set of super-heater tubes indicated at 25, the ends of the tubes being connected to inlet headers 26 and 27. A baille is arranged with a'portion 28 overlying the rear ends of the tubes 11 and a vertical portion '29 which protects the headers 26 and 27, while passing the gas along and through the spaces between the water tubes 11 and superheater tubes 25.

Above the superheater there is located a bank of inclined tubes 30 functioning with a separate circulation. The vertical portion 29 of the baille extends upward through the greater portion of the height of this bank of tubes at about the middle of their length providing a substantially constant area for the passage of the gas up one side of the baille and down the otherside as shown by the dotted arrows. Or the baffle may be located where it will provide a constant velocity of the gas instead of a constant area.

The front wall 31 of the casing is continuous. Theroof 32 slopes upward toward the back to give room for gas circulation. The back wall comprises an upper section 33 extending from 65 the roof to the bottom of the bank of tubes 30 and a lower section 34 extending from the tubes 11 to the bottom of the combustion chamber.

Between the two sections of the back wall is an opening leading to a flue 35 which conductsthe 70 gas through the usual economizer and air preheater to the stack.

The upper bank of tubes 30 has a separate circulation through outlet headers 36, circulating pipes 37, drum 38, down .pipes 39 and inlet head- 75 ers 40.

The tubes 30 need not be of the same length as the tubes l1 which are directly over the combustion chamber. The lattermay advantageously be made longer.

The several combinations of steam generating tubes described may be used in various types of furnace and with any kind of fuel. A row of nozzle burners 41 is indicated for pulverized coal,

oil or gas. Or the furnace maybe grate or stoker The two groups of tubes described serve practically as separate boilers insofar as the circulation is concerned. There is always a tendency in the tubes nearest the iire to develop a more energetic and rapid circulation than in those which, are more remote. By dividing the tubes according to thisv invention such rapid circulation is most eiiicient. At the same time the residual heat in the gas is used advantageously in the second set of tubes.

The circulation of gas is also very eflicient with this invention. There are no connections between the rear ends of the two banks of tubes to interfere with the free passage of the gas at this point The two circulating systems may' be tied together before taking oir the steam by the installation of a third drum 42 at a higher elevation than 105 the drums 16 and 38 and connected to these by circulating pipes such as 43 and 44 at each side.

A baille 45 -in the drum separates the water at the two sides. 'Ihe steam, however, passes out from both sides through an outlet pipe 46 which 110l leads by a pipe 47 to the inlet 26 of the superheater.

The steam may be taken off from the superheater header 27. But it is preferable to provide a supplementary radiant superheater consisting `of upright tubes 48 alternating with the tubes 20 within the combustion chamber at the back. These tubes have their upper ends bent outward and entering an outside header 49 from which the steam is taken off. Their lower ends are bent outward and enter a header 50 which receives steam from downcomers 51, whose upper ends communicate with tle header 27.

In Fig. 3 there is illustrated a similar arrangement of tubes 11 and 30 overhead and upright tubes 20 and 24 forming `combustion chamber water'walls. The bottom screen of water tubes, however, is omitted and separate downcomers 52 are illustrated for conducting water to the front bottom header 23.

This gure also illustrates al different control of the steam from the drums 16 and 38. There are two sets of superheater tubes 53 and 54 between the banks of inclined tubes 1l and 30. The steam from the tubes nearest the fire and having the most energetic circulation passes from the drum 16 through pipes 55, 56 and 57 to the inlet header 58 of the superheater 54, thence to the outlet header 59 andby the downcomers 51 to the radiant superheater and out through the header 49.

The steam from the slower circulation, however, passes from the drum 38 through pipes 60, 6l and 62 to the header 63 of the superheater 53 and thence to the outlet header 64 and by pipe 65 to the point of consumption without being subjected to the radiant superheating. The steam in this less energetic circuit does not require superheating to the same extent as that in the other circuit.

The steam may be taken off at dilerent pressures from the two circuits; preferably at comparatively low pressure from the outlet 65 and at comparatively high pressure from the outlet 49. More energetic firing will naturally increase the rate at which steam is generated in both circuits. The two superheating systems illustrated will provide steam at dierent temperatures. They may be proportioned so as to secure two supplies of steam either at the same temperature or at any desired different temperatures.

The two circuits including separate drums 16 and 38 may be used also to deliver steam to a single outlet without the intermediation of a third kment with Vthe third drum omitted. The steam is taken 01T by pipes 66 and 67 from the opposite drums. These pipes deliver to a common pipe 68 which conducts the steam to the inlet header 26. From this point the course is the same as for Fig. 1.

This figure also is used to illustrate the connections where the upright water walls or linings in the combustion chamber, shown in Figs. 1 and 3, are omitted. In Fig. 4 downcomers 69 conduct water from the steam drum 16 to a mud drum 70 which communicates-with the. lower ends of the headers 13 of the lower bank of tubes.

Fig. 5 shows the two independent circuits using a common drum 71. From the upper bank, the circuit is through the headers 36, circulatingpipes 37 and 39 and headers 40. From the lower bank the circulation is through headers 14, circulating pipes 72, drum 73, circulating pipes 74 and 75 and mud drum 70 to headers 13. Thesteam from the drum 71 passes by pipes 76 and 77 to the inlet header 26 of the superheater 25 and thence through the same course as in Fig. 1.

However, theV radiant superheater 48 with its headers and theconnections 51 may be omitted, the steam being taken to the point of consumption from the header 27 of the convection superheater 25.

Fig. 6 shows an arrangement similar to that of Fig. 5 but with a modification in the comparative lengths of the tubes in the two banks. The upper bank 30 is the sam'e as in the previous figures. The lower bank 78, however, is elongated to carry the rear 'ends of the tubes beyond those of the upper bank. Using longer tubes, we secure a better utilization of the radiant heat to which these tubes are exposed.

In Fig. 6 also there is illustrated the case in which the radiant superheater is omitted and the steam taken from the superheater 25 by a pipe 79.

The invention improves the operation of the boiler by avoiding interference between the circulation in the tubes which are more active (by being exposed to the radiant heat or by being the iirst with'which the burning gases contact) and those which are less active. The discharge of the gases between the upper and lower tubes is facilitated by avoiding any nipples or other connections between the upper and lower headers at the rear.

The invention permits the carryingV of two steam pressures in the same boiler unit, the part bounding or immediately around the combustion chamber supplying either a higher or a lower pressure (preferably higher) than the more remote part. Y

Another advantage is that the same boiler-unit can furnish super heat of different temperatures, which mightv be desirable for certain types of power station or industrial establishment.

A single casing comprising front and back walls 31, 33, 34 and side walls 80 (Fig. 2) and roof 32 encloses the two steam generating parts and accessories. It provides a simple path for the gases in the course of which their heat ls fully and advantageously applied to the steam generating pipes and' the superheaters. The shape and construction of the casing offers the minimum obstruction to the gas ow, excepting, of course that which is offered by the water and steam pipes which are purposely located in its path.

In all the previous figures the gases pass upward at one side of the transverse baffle 29 and then downward over and between the tubes 30 at the opposite side before passingout through the ue 35 carrying the usual economizer and air preheater. The outlet for the gases and combustion may be arranged in a variety of other ways and this is true in connection with each of the constructions shown in the several previous figures.

Fig. 7 shows a modication in this respect in connection with the arrangement of Fig. 3. In addition to the flue 35 there is provided a iiue 80 which takes the gases off from above the water tubes so that' it is not compelled to pass a second time over these tubes at the left side. The gas taken 01T is thus hotter. The ue 80 may include an economizer and an air preheater, just as the flue 35 does.

Or, the ue 35 may carry only an air preheater and the ue 8() carry an economizer, this generally calling for the use of higher temperature gases than air preheaters. Or any other arrangement may be provided within the flues for utilizing the residual heat. In fact a flue like 80, taking off frOm the top of the boiler may be alone used,

omitting the fiue 35. Assuming the two uesto be used there are dampers 81 and 82 in the respective flues by which the relative quantities of gas taken off through them can be controlled, or the gas may be shutoff entirely from one or the other.

The several-features of construction illustrated and described in connection with the diiferent gures may be used in the combination shown and in various other combinations. Generally, the modifications described for any one of the figures may be applied equally to the basic arrangements shown in the other figures.

Various other modifications may be made by those skilled in the art without departing from the invention as defined in the following claims.

I claim:

l. A steam generator having a casing in the in the upper part of which are two banks of approximately horizontal steam generating tubes with an open space between one bank and the other, means for circulating water and steam through said tubes, and means for directing the heating gases from the combustion chamber upward through the first and second banks of tubes and then downward over the second bank and then into said open space and out of the casing, the passage from said open space to the outside of the casing being unrestricted by the steam generating and circulating elements of the apparatus.

2. A steam generator having a casing in which are two banks of Water tubes one immediately over the combustion chamber of the furnace so as to be exposed directly to the burning gases and a second beyond the first so as to be heated by convction of the gases which have passed over the rst, baiiles overlying a portion of the rst bank and extending upward through the second bank and directing the gases upward through part vof the second bank and downward through another part, the two banks being spaced apart at the point where the downward current of gases emerges from the second bank and being entirely separate to permit free egress of the gases out of the casing.

3. A steam generator comprising a casing in which are two banks of water tubes, one beyond the other in the path of the heating gases, means for maintaining a circulation through one bank which is independent of that through the other, said banks havingan open space between them which is unrestricted by steam generating and circulating elements, bafiles for directing the heating gases forward over said banks of tubes and backward to said open space, and an exit ilu leading out from said open space.

4. A steam generator comprising two banks of water tubes, the rst being immediately over the combustion chamber of the furnace and the second being beyond the first, means for maintaining a circulation through one bank which is independent of that through the other, said banks having an open space between them which is unrestricted by steam generating and circulating elements, bales for directing the heating gasesforward over said banks of tubes and backward to said open space, and an exit ue leading out from said open space.

5. A steam generator comprising two banks of water tubes, the rst extending approximately horizontally immediately over the combustion chamber-of thefurnace and the second being substantially parallel to and above the iirst, means for maintaining a circulation through one bank independent of that through the other, said banks having an open space between them which is unrestricted by steam generating and circulating elements, bailles for directing the heating gases forward over said banks of tubes and backward to said open space, and an exit iiue leading out from said open space.

6. A steam generator comprising two banks of water tubes, the rst being immediately over the combustion chamber of the furnace and the second being beyond the rst, upright water tubes in the combustion chamber, means for maintaining a circulation through said rst bank and said upright tubes independent of the circulation through the second bank, said banks having anopen space between them which is unrestricted by steam generating and circulating elements, bailes for directing the heating gases forward over said banks of tubes and backward to said open space, and an exit flue leadingout from said open space.

'7. A steam generator comprising two banks of water tubes, the rst being immediately over yso the combustion chamber of the furnace and the second being beyond the first, upright water tubes in the combustion chamber, a bottom screen y of water tubes in said chamber, means for maintaining a circulation through said first bank and said upright tubes and said water screen which is independent of the -circulation through the second bank, said banks having an open space between them which is unrestricted by steam generating and circulating elements, baffles for directing the heating gases forward over said banks vof tubes and backward to said open space, and

an exit flue leading out from said open space.

8. A.steam generator comprising two banks of water tubes, one beyond the other in the path of the heating gases, a superheater between the two, means for maintaining a circulation through one bank which is independent of that through the other, said banks having an open space between them which is unrestricted by steam generating and circulating elements, baliles for directing the heating gases forward over said banks of tubes and backward to said open space, and an exit ue leading out from said open space.

9. A steam generator comprising two banks of waterv tubes, one beyond the other in the path of the heating gases and a separate circuit for each bank, each circuit including a superheater, a steam drum from which steam passes to said superheater and circulating pipes for conducting wet steam from the tubes to the drum and returning water from the same drum to the same tubes, the two banks of tubes being spaced apart and the two superheaters being positioned in the space between them.

l JAY A. FREIDAY. 

